There is nothing intrinsically wrong with SL: it's simplicity is what is lacking from any number of other programmes.
The trick with it is to introduce people to lifting in order to find out what works for them and what does not.
So, for instance, you may now feel you need to work on other body parts with equal measure to the squat, and so adjust your routine to suit. Or if you fail a lift, you might just chalk it up as a bad lift and carry on. At the end of the day, you are the best judge of how you're doing and what works, assuming you can be objective and honest with yourself.
For instance, I started out on SL two years ago, and was then moved to a different routine by one of my coaches. This then was reviewed and updated a couple of times before I decided on what worked for me and what I enjoyed and wanted. Hence my rather repetitive log ("Oh, look - more clean work! That's... exactly the same as the previous entry?!?!?!").
I am familiar enough with my training, how it affects me and how I need to get where I want to manage/monitor my own workouts... is this approach right for everybody? No, but then I am willing to experiment on myself to get what I want.
Take a look at some of the other routines around here to determine whether you like the look of them and give them a try for a couple of wkees and see how you get on. There is - ultimately - no right/wrong answer...